Classification: Hydrangea serrataxc3x97macrophylla xe2x80x98Lanarth Whitexe2x80x99xc3x97Hydrangea serrata xe2x80x98Blue Billowxe2x80x99.
Varietal denomination: The new plant has the varietal denomination xe2x80x98Sweet Carolxe2x80x99.
The present invention relates to a new and distinct variety of Hydrangea hybrid, which was developed in a controlled breeding program in Silver Spring, Md., United States, by Mr. Joseph Gray.
The genus Hydrangea is included in the family Saxifragaceae which comprises about 80 genera and 1,200 species of herbs, shrubs, small trees and woody climbers mostly temperate in origin. Hydrangea comprises approximately 23 species of deciduous or evergreen shrubs and vines originating in North America, South America and East Asia, many of which possess desirable ornamental characteristics. Recent taxonomical treatments sometimes isolate Hydrangea in a new family, Hydrangeaaceae. 
Hydrangea macrophylla is widespread and common throughout much of Japan. It generally has opposite, simple leaves, obovate to elliptic in shape, 10 to 20 cm long and 5 to 15 cm wide. Leaf color ranges from light to dark green, depending on light intensity and cultural conditions. Leaves are generally softly pubescent. Flower color is dependent upon the pH level of the soil and the amount of available aluminum in the soil media. Flowers of Hydrangea macrophylla are borne in mostly sterile florets, formed in what is often called a xe2x80x9chortensiaxe2x80x9d flower.
Hydrangea serrata is widespread and common throughout much of Japan, Korea and China. It generally has opposite, simple leaves, lanceolate in shape with acuminate apices, 5 to 15 cm long and 5 to 10 cm wide. Leaf color ranges from light to dark green, depending on light intensity and cultural conditions. Leaves are generally softly pubescent. The plant is deciduous. Flower color is dependent upon the pH level of the soil and the amount of available aluminum in the soil media. Flowers of Hydrangea serrata are borne in mostly flattened corymbs, 1 to 5 cm wide, with up to 12 sterile florets.
The new variety was discovered in a controlled breeding program of Hydrangea serrata and H. serrataxc3x97macrophylla, and differs from its parents in its large lacecap inflorescence, which is reminiscent of its macrophylla lineage, while being substantially hardier than macrophylla cultivars; the white-eye zone on sterile inflorescences when young; deeply serrated leaves; and merlot colored fall foliage. Asexual reproduction of the new variety by stem cuttings, performed in Silver Springs, Md. and Vacaville, Calif., have confirmed that the distinctive characteristics of the new variety are stable and transmitted to succeeding generations, and the new variety reproduces true to type.
xe2x80x98Sweet Carolxe2x80x99 is distinguished from its parents and all other varieties of Hydrangea of which I am aware in its large lacecap inflorescence, which is reminiscent of its macrophylla lineage, while being substantially hardier than macrophylla cultivars; the white-eye zone on sterile inflorescences when young; deeply serrated leaves, and merlot colored fall foliage.
The closest known cultivar to xe2x80x98Sweet Carolxe2x80x99 is Hydrangeaxc3x97xe2x80x98Sweet Chrisxe2x80x99 (U.S. Patent Pending; Ser. No. 10/357,938). xe2x80x98Sweet Carolxe2x80x99 exhibits larger flower panicles and larger and more recurved outer florets than xe2x80x98Sweet Chrisxe2x80x99. Additionally, xe2x80x98Sweet Carolxe2x80x99 and xe2x80x98Sweet Chrisxe2x80x99 differ in flower color, and the stems of xe2x80x98Sweet Carolxe2x80x99 are green as compared to the reddish colored stems of xe2x80x98Sweet Chrisxe2x80x99.